The present invention relates generally to printing apparatus and more particularly to a method and apparatus for cleaning gripper assemblies on printing presses.
A continuing problem in the operation of printing presses having gripper assemblies thereon is that paper lint and other particulate matter may collect on the gripper assemblies. One example of such particulate matter is powder which is sprayed onto freshly printed sheets so that when the sheets are stacked they are separated from one another by very thin layers of powder. Accumulation of powder, paper lint and the like is undesirable because small amounts of such matter may fall from the gripper assembly onto printed sheets, staining the sheets. Also, accumulation of such matter may interfere with opening and closing of the grippers.
In the past, deposits of such matter on gripper assemblies have generally been removed by directing pressurized air at the grippers to blow the matter off of them or by using a small broom or the like to brush it away. Neither of these methods has been satisfactory. With either of these methods, some of the powder removed from the grippers typically becomes suspended in the air and may settle on adjacent presses or other equipment. Cleaning with a brush is very time consuming. Cleaning with compressed air is messy, as particulate matter may be blown over a wide area.
Another approach has been to manually spray the grippers with a lubricating solution which cleans and lubricates the grippers simultaneously. However, such spraying has been, unsatisfactory for several reasons. First, use of such spray contaminates the surrounding environment, and commercially available lubricants which have been used in the past have been found to leave unpleasant odors after cleaning. A second problem is that the configuration of the press may restrict access to certain parts of the gripper assembly. Thus, it may be difficult to position a spray unit or hose in an orientation to direct the spray at all parts of the grippers, and it may be difficult for the person cleaning the grippers to see the parts being cleaned. A third problem is that manual spraying typically leaves excess lubricant on the grippers, and such excess lubricant tends to collect powder, paper lint and/or other particulate matter during operation of the press.